U.S. patent application number 16/850478 was filed with the patent office on 2020-07-30 for airtrap, system and method for removing microbubbles from a fluid stream.
The applicant listed for this patent is Baxter International Inc. Baxter Healthcare S.A.. Invention is credited to Carlos Corrales, Jorge DelCastillo, James Laird, Matthew Muller, Mark Perry, Atif Yardimci.
Application Number | 20200237993 16/850478 |
Document ID | 20200237993 / US20200237993 |
Family ID | 1000004781265 |
Filed Date | 2020-07-30 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200237993 |
Kind Code |
A1 |
Perry; Mark ; et
al. |
July 30, 2020 |
AIRTRAP, SYSTEM AND METHOD FOR REMOVING MICROBUBBLES FROM A FLUID
STREAM
Abstract
An airtrap for a medical or physiological fluid in one
embodiment includes a conical housing having a radius that
increases from its top to its bottom when the housing is positioned
for operation; a medical or physiological fluid inlet located at an
upper portion of the conical housing; a medical or physiological
fluid outlet located at a lower portion of the conical housing, the
inlet and the outlet positioned and arranged so that medical or
physiological fluid spirals in an increasing arc around an inside
of the conical housing downwardly from the inlet to the outlet; and
a gas collection area located at an upper portion of the conical
housing. In another embodiment, the airtrap is shaped like a
seahorse having a head section and a tail section. Any of the
airtraps herein may be used for example in blood sets, peritoneal
dialysis cassette tubing, and drug delivery sets.
Inventors: |
Perry; Mark; (McHenry,
IL) ; DelCastillo; Jorge; (Des Plaines, IL) ;
Muller; Matthew; (Lindenhurst, IL) ; Corrales;
Carlos; (Vernon Hills, IL) ; Yardimci; Atif;
(Lake Forest, IL) ; Laird; James; (Grayslake,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Baxter International Inc.
Baxter Healthcare S.A. |
Deerfield
Glattpark (Opfikon) |
IL |
US
CH |
|
|
Family ID: |
1000004781265 |
Appl. No.: |
16/850478 |
Filed: |
April 16, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15046048 |
Feb 17, 2016 |
10625009 |
|
|
16850478 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 1/3638 20140204;
A61M 1/1658 20130101; A61M 1/3486 20140204; A61M 2205/7536
20130101; B01D 19/0057 20130101; A61M 5/36 20130101; A61M 1/28
20130101; A61M 2206/16 20130101; A61M 1/3679 20130101; A61M
2205/123 20130101; A61M 5/385 20130101; A61M 1/3627 20130101 |
International
Class: |
A61M 1/16 20060101
A61M001/16; A61M 5/38 20060101 A61M005/38; A61M 1/36 20060101
A61M001/36; A61M 1/28 20060101 A61M001/28; A61M 1/34 20060101
A61M001/34; B01D 19/00 20060101 B01D019/00; A61M 5/36 20060101
A61M005/36 |
Claims
1. An airtrap for a medical or physiological fluid comprising: a
head section having (i) a largest diameter extending perpendicular
to a plane bisecting the airtrap or (ii) a largest width and height
extending perpendicular to the plane bisecting the airtrap; a
medical or physiological fluid inlet provided by the head section;
a tubular tail section, which when the airtrap is mounted for
operation extends downwardly from the head section, the tubular
tail section smaller in (a) diameter or (b) largest cross-sectional
distance than (i) the largest diameter of the head section or (ii)
the largest width or height of the head section, the tubular tail
section including at least one smooth curve, jog and/or undulation
positioned and arranged to cause fluid flowing from the head
section, through the tubular tail section, to change direction at
least one time; and a medical or physiological fluid outlet located
at a distal end of the tubular section, beneath the medical or
physiological fluid inlet when the airtrap is mounted for
operation, such that air rises to a top of the head section via
buoyancy, and wherein the at least one smooth curve, jog and/or
undulation helps to dislodge air from the medical or physiological
fluid.
2. The airtrap of claim 1, wherein the medical or physiological
fluid outlet at the distal end of the tail section extends
generally horizontally when the airtrap is mounted for
operation.
3. The airtrap of claim 1, wherein the medical or physiological
fluid inlet provided by the head section extends generally
horizontally when the airtrap is mounted for operation.
4. The airtrap of claim 1, wherein the (a) diameter of the tubular
tail section or (b) largest cross-sectional distance of the tail
section narrows as it extends from the head section to the medical
or physiological fluid outlet at the distal end of the tail
section.
5. The airtrap of claim 1, wherein the top of the head section
includes an enlarged upper area for air collection.
6. The airtrap of claim 1, which includes a gas release valve
located at an opening in the top of the head section.
7. The airtrap of claim 6, wherein the gas release valve is a check
valve.
8. The airtrap of claim 6, wherein the gas release valve includes a
seal that stretches to open under gas pressure and self-closes once
the gas pressure is released.
9. The airtrap of claim 1, which includes a hydrophobic membrane
located beneath the top of the head section.
10. The airtrap of claim 1, which includes a resealable septum
located at an opening in the top of the head section.
11. The airtrap of claim 1, which is in the shape of a
seahorse.
12. The airtrap of claim 1, which is provided in a blood set for
operation with a blood pump.
13. The airtrap of claim 1, which is provided in a venous line of
the blood set.
14. The airtrap of claim 1, which is provided in a patient line in
fluid communication with a disposable cassette for operation with a
dialysis fluid pump.
15. The airtrap of claim 1, which is provided in a drug delivery
line of a drug delivery set for operation with the drug delivery
pump.
16. An airtrap for a medical or physiological fluid comprising: a
conical housing having a radius that decreases from its top to its
bottom when the housing is positioned for operation; a medical or
physiological fluid inlet located at an upper portion of the
conical housing; a medical or physiological fluid outlet located at
a lower portion of the conical housing, the inlet and the outlet
positioned and arranged so that medical or physiological fluid
spirals in a decreasing arc around an inside of the conical housing
downwardly from the inlet to the outlet; and a gas collection area
located at the upper portion of the conical housing.
17. The airtrap of claim 16, which has a toroidal top leading to an
inner cone.
18. The airtrap of claim 16, which includes a gas release valve
located at an opening in the upper portion of the conical
housing.
19. The airtrap of claim 18, wherein the gas release valve is a
check valve.
20. The airtrap of claim 19, wherein the gas release valve includes
a seal that stretches to open under gas pressure and self-closes
once the gas pressure is released.
Description
PRIORITY CLAIM
[0001] This application is a continuation of application of U.S.
patent application Ser. No. 15/046,048, filed Feb. 17, 2016,
entitled "AIRTRAP, SYSTEM AND METHOD FOR REMOVING MICROBUBBLES FROM
A FLUID STREAM", the entire contents which are incorporated herein
by reference and relied upon.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application is related in subject matter to commonly
owned (i) U.S. Pat. No. 7,871,462, issued Jan. 18, 2011, entitled
"Dialysis Systems Having Air Separation Chambers with Internal
Structures to Enhance Air Removal", filed Oct. 1, 2007; (ii) U.S.
Pat. No. 7,892,331, issued Feb. 22, 2011, entitled "Dialysis
Systems Having Air Separation Chambers with Internal Structures to
Enhance Air Removal", filed Oct. 1, 2007; (iii) U.S. Pat. No.
7,892,332, issued Feb. 22, 2011, entitled "Dialysis Systems Having
Airtraps with Internal Structures to Enhance Air Removal", filed
Oct. 1, 2007; (iv) U.S. Pat. No. 7,988,768, issued Aug. 2, 2011,
entitled "Dialysis Systems Having Spiraling Fluid Air Separation
Chambers", filed Dec. 28, 2010; (v) U.S. Pat. No. 8,025,716, issued
Sep. 27, 2011, entitled "Fluid Delivery Systems and Methods Having
Floating Baffle Aided Air Removal", filed Feb. 18, 2011; (vi) U.S.
Pat. No. 8,080,091, issued Dec. 20, 2011, entitled "Dialysis
Systems and Methods Including Cassette with Fluid Heating and Air
Removal", filed Feb. 18, 2011, and (vii) U.S. Pat. No. 8,221,529,
issued Jul. 17, 2012, entitled "Dialysis Systems and Methods
Including Cassette With Air Removal", filed Feb. Nov. 21, 2011.
BACKGROUND
[0003] The present disclosure relates generally to air removal
devices, systems and methods for liquid delivery systems. More
specifically, the present disclosure relates to air removal
devices, systems and methods for medical fluid delivery, such as
blood, dialysis fluid, substitution fluid or intravenous drug
delivery.
[0004] Due to various causes, a person's renal system can fail.
Renal failure produces several physiological derangements. It is no
longer possible to balance water and minerals or to excrete daily
metabolic load. Toxic end products of nitrogen metabolism (urea,
creatinine, uric acid, and others) can accumulate in blood and
tissue.
[0005] Kidney failure and reduced kidney function have been treated
with dialysis. Dialysis removes waste, toxins and excess water from
the body that normal functioning kidneys would otherwise remove.
Dialysis treatment for replacement of kidney functions is critical
to many people because the treatment is life saving.
[0006] One type of kidney failure therapy is Hemodialysis ("HD"),
which in general uses diffusion to remove waste products from a
patient's blood. A diffusive gradient occurs across the
semi-permeable dialyzer between the blood and an electrolyte
solution called dialysate or dialysis fluid to cause diffusion.
[0007] Hemofiltration ("HF") is an alternative renal replacement
therapy that relies on a convective transport of toxins from the
patient's blood. HF is accomplished by adding substitution or
replacement fluid to the extracorporeal circuit during treatment
(typically ten to ninety liters of such fluid). The substitution
fluid and the fluid accumulated by the patient in between
treatments is ultrafiltered over the course of the HF treatment,
providing a convective transport mechanism that is particularly
beneficial in removing middle and large molecules (in hemodialysis
there is a small amount of waste removed along with the fluid
gained between dialysis sessions, however, the solute drag from the
removal of that ultrafiltrate is not enough to provide convective
clearance).
[0008] Hemodiafiltration ("HDF") is a treatment modality that
combines convective and diffusive clearances. HDF uses dialysis
fluid flowing through a dialyzer, similar to standard hemodialysis,
to provide diffusive clearance. In addition, substitution solution
is provided directly to the extracorporeal circuit, providing
convective clearance.
[0009] Most HD (HF, HDF) treatments occur in centers. A trend
towards home hemodialysis ("HHD") exists today in part because HHD
can be performed daily, offering therapeutic benefits over
in-center hemodialysis treatments, which occur typically bi- or
tri-weekly. Studies have shown that more frequent treatments remove
more toxins and waste products than a patient receiving less
frequent but perhaps longer treatments. A patient receiving more
frequent treatments does not experience as much of a down cycle as
does an in-center patient, who has built-up two or three days worth
of toxins prior to a treatment. In certain areas, the closest
dialysis center can be many miles from the patient's home causing
door-to-door treatment time to consume a large portion of the day.
HHD can take place overnight or during the day while the patient
relaxes, works or is otherwise productive.
[0010] Another type of kidney failure therapy is peritoneal
dialysis, which infuses a dialysis solution, also called dialysis
fluid, into a patient's peritoneal cavity via a catheter. The
dialysis fluid contacts the peritoneal membrane of the peritoneal
cavity. Waste, toxins and excess water pass from the patient's
bloodstream, through the peritoneal membrane and into the dialysis
fluid due to diffusion and osmosis, i.e., an osmotic gradient
occurs across the membrane. An osmotic agent in dialysis provides
the osmotic gradient. The used or spent dialysis fluid is drained
from the patient, removing waste, toxins and excess water from the
patient. This cycle is repeated, e.g., multiple times.
[0011] There are various types of peritoneal dialysis therapies,
including continuous ambulatory peritoneal dialysis ("CAPD"),
automated peritoneal dialysis ("APD"), tidal flow dialysis and
continuous flow peritoneal dialysis ("CFPD"). CAPD is a manual
dialysis treatment. Here, the patient manually connects an
implanted catheter to a drain to allow used or spent dialysate
fluid to drain from the peritoneal cavity. The patient then
connects the catheter to a bag of fresh dialysis fluid to infuse
fresh dialysis fluid through the catheter and into the patient. The
patient disconnects the catheter from the fresh dialysis fluid bag
and allows the dialysis fluid to dwell within the peritoneal
cavity, wherein the transfer of waste, toxins and excess water
takes place. After a dwell period, the patient repeats the manual
dialysis procedure, for example, four times per day, each treatment
lasting about an hour. Manual peritoneal dialysis requires a
significant amount of time and effort from the patient, leaving
ample room for improvement.
[0012] Automated peritoneal dialysis ("APD") is similar to CAPD in
that the dialysis treatment includes drain, fill and dwell cycles.
APD machines, however, perform the cycles automatically, typically
while the patient sleeps. APD machines free patients from having to
manually perform the treatment cycles and from having to transport
supplies during the day. APD machines connect fluidly to an
implanted catheter, to a source or bag of fresh dialysis fluid and
to a fluid drain. APD machines pump fresh dialysis fluid from a
dialysis fluid source, through the catheter and into the patient's
peritoneal cavity. APD machines also allow for the dialysis fluid
to dwell within the cavity and for the transfer of waste, toxins
and excess water to take place. The source may include multiple
sterile dialysis fluid solution bags.
[0013] APD machines pump used or spent dialysate from the
peritoneal cavity, though the catheter, and to the drain. As with
the manual process, several drain, fill and dwell cycles occur
during dialysis. A "last fill" occurs at the end of APD and remains
in the peritoneal cavity of the patient until the next
treatment.
[0014] In any of the above modalities, entrained air and other
gases are a concern. Entrained air can cause inaccuracies when
pumping dialysis fluid for any of PD, HD, HF, HDF, other blood
treatment modalities such continuous renal replacement therapy
("CRRT") treatment, and intravenous drug delivery. Entrained air
can cause a reduction in effective surface area in a hemodialysis
filter when it accumulates on the filter fibers, leading to a
reduction in effectiveness of the therapy. Entrained air entering a
patient's peritoneum during PD can cause discomfort.
[0015] Regarding an extracorporeal blood therapy (e.g. HD, HF, HDF,
CRRT), a gas phase may be present in the blood arising from leakage
into an otherwise closed system from the outside (e.g. air sucked
in via pumping), residual air not effectively primed from the
device at the start of therapy, gas evolving from the blood plasma
and cellular compartments (e.g. oxygen, carbon dioxide and
nitrogen), and/or gas transported across a membrane from the
dialysis fluid side (e.g. carbon dioxide from bicarbonate
solution). While different gases may dominate in certain
situations, air (78% nitrogen, 21% oxygen, 1% others) is the most
typical gas. The term "air" as used herein may mean air (78%
nitrogen, 21% oxygen, 1% others), while the term gas includes air
and/or any other gas, e.g., carbon dioxide.
[0016] An air embolism during a blood treatment may occur when a
bolus of air is infused into the patient. As little as 20 ml of air
can be dangerous when introduced directly into the patient's blood
system. One of the most common risks for a venous air embolism is
an empty intravenous ("IV") saline bag during rapid infusions for
cramps and during a final blood rinse-back.
[0017] Microbubbles circulating in the extracorporeal circuit may
present hazards when returned to patients. Microbubbles may
originate in extracorporeal tubing, circulate in the blood stream
until lodging in the capillary bed of various organs, mainly the
lungs. During its course within the capillary, a bubble abrades the
glycocalyx layer lining the surface of the vessels and thereafter
obstructs blood flow through the capillary. This causes tissue
ischemia, inflammatory response, and complement activation.
Aggregation of platelets and clot formation may occur as well,
leading to further obstruction of the microcirculation and
subsequent tissue damage.
[0018] Microbubbles in the extracorporeal circuit may also
contribute to platelet activation, fouling of blood-wetted surfaces
with protein deposits, and flow blockages. Accumulation of bubbles
in blood set recirculation zones may form foam having a high
surface area, which accelerates clotting. Clots block flow through
dialyzer fibers and the return fistula needle. Gas bubble induced
clotting may also limit the reuse of dialyzers and blood sets.
[0019] Dialysis patients using catheter-based treatments are at the
highest risk of venous air embolism since any air is introduced
directly into the central blood vessels immediately. Ensuring that
the catheter is clamped securely before connecting or disconnecting
bloodlines limits the risk of venous air embolism. However, a
venous catheter crack or disconnection may go unnoticed.
[0020] It should also be appreciated that air may be an issue for
other treatments requiring the delivery of a fluid to a patient,
such as PD and intravenous drug delivery.
[0021] For each of the above reasons and scenarios, a need exists
to provide an apparatus that ensures that entrained air is removed
from blood, dialysis fluid, substitution fluid or an intravenous
drug during treatment and prior to delivering or returning such
fluids to the patient.
SUMMARY
[0022] The examples described herein disclose air removal devices,
systems and methods applicable, for example, to fluid delivery for:
plasmapherisis, hemodialysis ("HD"), hemofiltration ("HF")
hemodiafiltration ("HDF"), and continuous renal replacement therapy
("CRRT") treatments. The air removal devices, systems and methods
described herein are also applicable to peritoneal dialysis ("PD")
and to intravenous drug delivery. These modalities may be referred
to collectively or generally individually as medical fluid
delivery.
[0023] Moreover, each of the devices, systems and methods described
herein may be used with clinical or home-based machines. For
example, the systems may be employed in in-center HD, HF or HDF
machines, which run throughout the day. Alternatively, the systems
may be used with home HD, HF or HDF machines, which are operated at
the patient's convenience. One such home system is described in
U.S. Pat. No. 8,029,454 ("the '454 patent"), issued Oct. 4, 2011,
entitled "High Convection Home Hemodialysis/Hemofiltration And
Sorbent System", filed Nov. 4, 2004, assigned to the assignee of
the present application. Another such home system is described in
U.S. Pat. No. 8,721,884 ("the '884 patent"), issued May 13, 2014,
entitled "Hemodialysis Systems and Methods", filed Feb. 7, 2013.
The entire contents of each of the above references is incorporated
herein by reference and relied upon.
[0024] The air removal devices, systems and methods described
herein prevent large bolus injections of gas from being infused
into the patient, which may result in a pulmonary embolism. The
risks of microemboli that may result from infusion of microbubbles
are not as clear. The smaller bubbles may be digested in the venous
system or be passed through the pulmonary bed. In any case, the air
removal devices, systems and methods described herein also seek to
remove microbubbles from blood or medical fluid before being
infused into the patient.
[0025] The airtraps discussed herein seek to minimize
extracorporeal blood clotting. The airtraps may accordingly use
blood compatible materials, minimize gas foaming, resist clot
attachment to surfaces, avoid blood recirculation and stagnation,
and seek to minimize blood/material contact surface area. For
certain applications, the airtraps are disinfected between uses and
reused, e.g., thirty times or more. The airtrap materials are
therefore selected to survive and function after disinfection,
e.g., a chemical disinfection and/or a heat disinfection treatment
of approximately 80.degree. C. to 90.degree. C. over multiple,
e.g., thirty, disinfections or cycles. The airtraps are constructed
in an embodiment to resist clots attaching to their surfaces,
maximize wall shear when a wash mode is used to effectively remove
clots, and maintain a robust integral mechanical and
microbiological closure to withstand operating pressures. The
airtraps may also be constructed to minimize extracorporeal blood
or medical fluid volume, enhance the ability to be auto-primed,
present minimal blood flow pressure drop, and be optimized for
manufacturability.
[0026] The airtraps discussed herein in an embodiment have a large
enough volume to accept trapped air developed over an entire
medical fluid treatment. In alternative embodiments, the airtraps
have a considerably smaller volume and instead employ an air
removal technique. The air removal technique may be active, e.g.,
employ a sensor and one or more pump in communication with a
controller. In another embodiment, the air removal technique is
passive, e.g. employs a filter and/or valve that enables separated
air to be purged via pressure built inside the airtrap. In a
further alternative embodiment, the air removal technique is
manual, e.g., includes a septum allowing air to be withdrawn via a
needle.
[0027] In one embodiment, the airtrap includes a conically shaped
housing. Blood or medical fluid enters through an inlet at the top
of the conically shaped housing, flows around and spirals downward
along an interior, ever-increasing diameter, conical wall of the
housing and exits through an outlet at the bottom of the conically
shaped housing. Entrained air is separated centrifically towards
the center and is moved buoyantly upward. Air or gas accumulates in
a quiet upper region of the conical housing, where it is held at
pressure. In a passive air removal embodiment, the air may be held
at pressure against a hydrophobic membrane and/or a check or
one-way valve, e.g., silicone, which allow the air to be passively
released from the housing, while preventing outside, non-sterile
air from entering the airtrap. Typical pressures may be 100 to 300
mmHg at a blood or medical fluid flow rate of 400 ml/min. Gas
passes through the membrane, while blood is retained.
[0028] The conical housing airtrap in an embodiment includes an
interior housing cone that extends up into the exterior housing
cone to provide further aid in the spiraling of the blood or
medical fluid, aiding the centripetal removal of small gas bubbles.
The conical housing airtrap improves the separation of gas from
blood or medical fluid, which is ejected to atmosphere, while
avoiding therapy interruption to manually aspirate air. The conical
housing airtrap greatly reduces emboli risk and risk for
micoremboli, thereby reducing risks for clots, tissue ischemia and
inflammation. Since the airtrap effectively eliminates gas bubbles
and microbubbles, the tendency for clotting in the extracorporeal
set is diminished. The conical housing airtrap remains sterile or
near sterile throughout treatment, does not affect system priming,
prevents air ingress and employs blood compatible plastic and/or
metal materials, such as silicone or medical grade stainless steel
housing materials, polyvinylidene fluoride or polyvinylidene
difluoride ("PVDF") or polysulfone membrane or filter materials,
and silicone valve. Other materials, such as Kynar or
silicone-based or silicone-coated materials may be employed
alternatively for the housing.
[0029] In an alternative embodiment, the airtrap again has a
conical shape, but here the cone narrows in diameter as it extends
from top to bottom. The top of the cone extends down into itself,
forming an inner obstruction or slender cone that extends within
the outer housing cone. The outer and inner cone shapes cause fluid
within the airtrap to spin in a vortex, creating a centripetal
force that forces heavier fluid outwardly and lighter air to
release at the inside of the airtrap and rise buoyantly to a quiet
zone at the top of the conical housing. Degassed fluid exits the
conical housing at its bottom. Blood or medical fluid flows in a
circular path, spiraling down to the outlet, creating no eddy
currents in an embodiment. A volume may be provided at the top of
the housing to collect trapped air, which may also include a septum
that is pierced by a syringe to pull air manually from the airtrap.
The alternative conical airtrap may have a hydrophobic membrane
and/or valve, and may be made of any of the materials discussed
above.
[0030] In a further alternative embodiment, the airtrap has a
housing shape similar to that of a seahorse. Blood or medical fluid
potentially containing air enters at the top or enlarged head
chamber of the seahorse housing. The blood or medical fluid spreads
and slows, allowing gas bubbles to follow a gentle slow flow and to
rise towards an upper ceiling of the head chamber. The gradually
changing shape of the head chamber allows fluid flow to slow
without forming eddies. Once blood or medical fluid flows past the
head chamber, the fluid is directed downwardly through a bending
and varying diameter of a tail section of the seahorse shape,
allowing additional opportunity for gas bubbles to rise towards the
head chamber ceiling. The chamber head and tail have no
obstructions to cause eddies in an embodiment, so fluid flows
through the seahorse airtrap, sweeping surfaces to minimize
clotting. A hump may be provided on the top of the head chamber for
storage volume for trapped air or gas. The streamline shape of the
chamber head and seahorse tail minimizes blood volume and surface
area contact. An alternative seahorse embodiments may have a
hydrophobic membrane and/or valve, and may be made of the materials
discussed above. Further alternatively, the seahorse embodiment
includes a septum that may be pierced by a syringe to pull air
manually from the airtrap.
[0031] Each of the airtrap embodiments described herein may be
provided as part of a blood set with other components, such as an
arterial line extending to a pumping chamber (membrane or
peristaltic), which extends to an arterial end of a dialyzer. A
venous line extends from a venous end of the dialyzer. One of the
airtraps is provided in the venous line in an embodiment. A second
(same or different airtrap) may optionally be placed in the
arterial line, e.g., between the blood pump and dialyzer so that
the airtrap is under positive pressure. The blood set may be single
use or configured for being disinfected between treatments and
reused over multiple treatments. In an embodiment, the airtrap
housing has clipping or grabbing structure formed with or attached
to the outer wall of the housing of the airtrap, so that the
airtrap may be clipped removeably to or grabbed removeably by a
blood treatment machine.
[0032] In a peritoneal dialysis application, any of the airtraps
described herein may be employed as part of the patient line
extending from the peritoneal dialysis machine to the patient. The
airtrap may be placed at a machine end of the patient line, so that
the airtrap may be clipped removeably to or grabbed removeably by
the peritoneal dialysis machine. The airtrap traps air going and
coming from the patient. Fluid coming from the patient will be
under negative pressure, such that a one-way valve will likely be
sealed shut. Trapped air may be purged however during the next fill
cycle when the patient line is under positive pressure.
[0033] In an intravenous drug delivery embodiment, the airtrap may
be placed in the patient line upstream or downstream of the drug
delivery pump (e.g., rotary peristaltic, linear peristaltic, or
shuttle), so that fluid within the airtrap is under positive
pressure. Placement of the airtrap upstream of the drug delivery
pump traps air prior to entering the pump, which can cause
therapy-interrupting alarms when sensed. The pulsatile filling
portion of the peristaltic pump stroke may reduce pressure causing
the one-way valve to seal shut and temporarily trap air. However,
positive head pressure from the source container will cause the
one-way valve to open to purge air during the ejection or pump-out
portion of the peristaltic or shuttle pump stroke. Placing the
airtrap downstream of the pump has the advantages of removing air
as a final check before delivery to the patient and readily
eliminating air because the line tends to be always in a state of
positive pressure. The airtrap may be placed at a machine end of
the drug delivery line, so that the airtrap may be clipped
removeably to or grabbed removeably by the drug delivery
machine.
[0034] In light of the disclosure herein and without limiting the
disclosure in any way, in a first aspect of the present disclosure,
which may be combined with any other aspect listed herein unless
specified otherwise, an airtrap for a medical or physiological
fluid includes: a conical housing having a radius that increases
from its top to its bottom when the housing is positioned for
operation; a medical or physiological fluid inlet located at an
upper portion of the conical housing; a medical or physiological
fluid outlet located at a lower portion of the conical housing, the
inlet and the outlet positioned and arranged so that medical or
physiological fluid spirals in an increasing arc around an inside
of the conical housing downwardly from the inlet to the outlet; and
a gas collection area located at the upper portion of the conical
housing.
[0035] In a second aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, the airtrap includes a gas release valve located at an
opening in the upper portion of the conical housing.
[0036] In a third aspect of the present disclosure, which may be
combined with the second aspect in combination with any other
aspect listed herein unless specified otherwise, the gas release
valve is a check valve.
[0037] In a fourth aspect of the present disclosure, which may be
combined with the second aspect in combination with any other
aspect listed herein unless specified otherwise, the gas release
valve includes a seal that stretches to open under gas pressure and
self-closes once the gas pressure is released.
[0038] In a fifth aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, the airtrap includes a hydrophobic membrane located
beneath an opening in the upper portion of the conical housing.
[0039] In a sixth aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, the medical or physiological fluid inlet is at least
substantially horizontally disposed when the airtrap is positioned
for operation.
[0040] In a seventh aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, the medical or physiological fluid outlet is at least
substantially horizontally disposed when the airtrap is positioned
for operation.
[0041] In an eighth aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, the top of the conical housing at the upper portion is
flat and defines a gas release outlet.
[0042] In a ninth aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, a bottom wall of the conical housing at the lower
portion of the conical housing rises within an outer conical wall
of the conical housing.
[0043] In a tenth aspect of the present disclosure, which may be
combined with the ninth aspect in combination with any other aspect
listed herein unless specified otherwise, the rising bottom wall
forms an inner conical wall inside of the outer conical wall.
[0044] In an eleventh aspect of the present disclosure, which may
be combined with the ninth aspect in combination with any other
aspect listed herein unless specified otherwise, the rising bottom
wall helps the medical or physiological fluid to spiral around the
inside of the conical housing.
[0045] In a twelfth aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, the gas collection area is located at an upper, central
portion of the conical housing.
[0046] In a thirteenth aspect of the present disclosure, which may
be combined with any other aspect listed herein unless specified
otherwise, the airtrap includes structure for being mounted in its
position for operation.
[0047] In a fourteenth aspect of the present disclosure, which may
be combined with any other aspect listed herein unless specified
otherwise, a renal therapy blood treatment system includes: a blood
pump; and a blood set for operation with the blood pump, the blood
set having an airtrap including a conical housing having a radius
that increases from its top to its bottom when the housing is
positioned for operation, a blood inlet located at an upper portion
of the conical housing, a blood outlet located at a lower portion
of the conical housing, the inlet and the outlet positioned and
arranged so that blood spirals around an inside of the conical
housing downwardly from the inlet to the outlet, and a gas
collection area located at an upper portion of the conical
housing.
[0048] In a fifteenth aspect of the present disclosure, which may
be combined with the fourteenth aspect in combination with any
other aspect listed herein unless specified otherwise, the blood
set includes an arterial line and a venous line, and wherein the
airtrap is located in the venous line.
[0049] In a sixteenth aspect of the present disclosure, which may
be combined with the fourteenth aspect in combination with any
other aspect listed herein unless specified otherwise, the renal
therapy blood treatment system includes a dialysis fluid circuit,
the airtrap a first airtrap, and which includes at least one second
conical airtrap located in the dialysis fluid circuit.
[0050] In a seventeenth aspect of the present disclosure, which may
be combined with the fourteenth aspect in combination with any
other aspect listed herein unless specified otherwise, the renal
therapy blood treatment system includes a chassis housing the blood
pump and including mounting features for removeably mounting the
airtrap in its position for operation.
[0051] In an eighteenth aspect of the present disclosure, which may
be combined with the fourteenth aspect in combination with any
other aspect listed herein unless specified otherwise, the blood
set is configured to be connected to a patient, and wherein the
airtrap aims to prevent air from reaching the patient.
[0052] In a nineteenth aspect of the present disclosure, which may
be combined with any other aspect listed herein unless specified
otherwise, a peritoneal dialysis system includes: a peritoneal
dialysis fluid pump; and a disposable cassette for operation with
the peritoneal dialysis fluid pump, the disposable cassette in
fluid communication with a patient line having an airtrap including
a conical housing having a radius that increases from its top to
its bottom when the housing is positioned for operation, a
peritoneal dialysis fluid inlet located at an upper portion of the
conical housing, a peritoneal dialysis fluid outlet located at a
lower portion of the conical housing, the inlet and the outlet
positioned and arranged so that peritoneal dialysis fluid spirals
around an inside of the conical housing downwardly from the inlet
to the outlet, and a gas collection area located at an upper
portion of the conical housing.
[0053] In a twentieth aspect of the present disclosure, which may
be combined with the nineteenth aspect in combination with any
other aspect listed herein unless specified otherwise, the
peritoneal dialysis system includes a chassis housing the
peritoneal dialysis fluid pump and including mounting features for
removeably mounting the airtrap in its position for operation.
[0054] In a twenty-first aspect of the present disclosure, which
may be combined with the nineteenth aspect in combination with any
other aspect listed herein unless specified otherwise, the patient
line is configured to be connected to a patient, and wherein the
airtrap aims to prevent air from reaching the patient.
[0055] In a twenty-second aspect of the present disclosure, which
may be combined with any other aspect listed herein unless
specified otherwise, an infusion pump system includes: a drug
delivery pump; and a drug delivery set for operation with the drug
delivery pump, the drug delivery set including a drug delivery line
having an airtrap, the airtrap including a conical housing having a
radius that increases from its top to its bottom when the housing
is positioned for operation, an intravenous drug inlet located at
an upper portion of the conical housing, an intravenous drug outlet
located at a lower portion of the conical housing, the inlet and
the outlet positioned and arranged so that an intravenous drug
spirals around an inside of the conical housing downwardly from the
inlet to the outlet, and a gas collection area located at an upper
portion of the conical housing.
[0056] In a twenty-third aspect of the present disclosure, which
may be combined with the twenty-second aspect in combination with
any other aspect listed herein unless specified otherwise, the
infusion pump system includes a chassis housing the drug delivery
pump and including mounting features for removeably mounting the
airtrap in its position for operation.
[0057] In a twenty-fourth aspect of the present disclosure, which
may be combined with the twenty-second aspect in combination with
any other aspect listed herein unless specified otherwise, the drug
delivery line is configured to be connected to a patient, and
wherein the airtrap aims to prevent air from reaching the
patient.
[0058] In a twenty-fifth aspect of the present disclosure, which
may be combined with any other aspect listed herein unless
specified otherwise, an airtrap for a medical or physiological
fluid includes: a head section having (i) a largest diameter
extending perpendicular to a plane bisecting the airtrap or (ii) a
largest width and height extending perpendicular to the plane
bisecting the airtrap; a medical or physiological fluid inlet
provided by the head section; a tubular tail section, which when
the airtrap is mounted for operation extends downwardly from the
head section, the tubular tail section smaller in (a) diameter or
(b) largest cross-sectional distance than (i) the largest diameter
of the head section or (ii) the largest width or height of the head
section, the tubular tail section including at least one smooth
curve, jog and/or undulation positioned and arranged to cause fluid
flowing from the head section, through the tubular tail section, to
change direction at least one time; and a medical or physiological
fluid outlet located at a distal end of the tubular section,
beneath the medical or physiological fluid inlet when the airtrap
is mounted for operation, such that air rises to a top of the head
section via buoyancy, and wherein the at least one smooth curve,
jog and/or undulation helps to dislodge air from the medical or
physiological fluid.
[0059] In a twenty-sixth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
medical or physiological fluid outlet at the distal end of the tail
section extends generally horizontally when the airtrap is mounted
for operation.
[0060] In a twenty-seventh aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
medical or physiological fluid inlet provided by the head section
extends generally horizontally when the airtrap is mounted for
operation.
[0061] In a twenty-eighth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the (a)
diameter of the tubular tail section or (b) largest cross-sectional
distance of the tail section narrows as it extends from the head
section to the medical or physiological fluid outlet at the distal
end of the tail section.
[0062] In a twenty-ninth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the top
of the head section includes an enlarged upper area for air
collection.
[0063] In a thirtieth aspect of the present disclosure, which may
be combined with the twenty-fifth aspect in combination with any
other aspect listed herein unless specified otherwise, the airtrap
includes a gas release valve located at an opening in the top of
the head section.
[0064] In a thirty-first aspect of the present disclosure, which
may be combined with the thirtieth aspect in combination with any
other aspect listed herein unless specified otherwise, the gas
release valve is a check valve.
[0065] In a thirty-second aspect of the present disclosure, which
may be combined with the thirtieth aspect in combination with any
other aspect listed herein unless specified otherwise, the gas
release valve includes a seal that stretches to open under gas
pressure and self-closes once the gas pressure is released.
[0066] In a thirty-third aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap includes a hydrophobic membrane located beneath the top of
the head section.
[0067] In a thirty-fourth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap includes a resealable septum located at an opening in the
top of the head section.
[0068] In a thirty-fifth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap is in the shape of a seahorse.
[0069] In a thirty-sixth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap is provided in a blood set for operation with a blood
pump.
[0070] In a thirty-seventh aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap is provided in a venous line of the blood set.
[0071] In a thirty-eighth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap is provided in a patient line in fluid communication with a
disposable cassette for operation with a dialysis fluid pump.
[0072] In a thirty-ninth aspect of the present disclosure, which
may be combined with the twenty-fifth aspect in combination with
any other aspect listed herein unless specified otherwise, the
airtrap is provided in a drug delivery line of a drug delivery set
for operation with the drug delivery pump.
[0073] In a fortieth aspect of the present disclosure, which may be
combined with any other aspect listed herein unless specified
otherwise, an airtrap for a medical or physiological fluid
includes: a conical housing having a radius that decreases from its
top to its bottom when the housing is positioned for operation; a
medical or physiological fluid inlet located at an upper portion of
the conical housing; a medical or physiological fluid outlet
located at a lower portion of the conical housing, the inlet and
the outlet positioned and arranged so that medical or physiological
fluid spirals in a decreasing arc around an inside of the conical
housing downwardly from the inlet to the outlet; and a gas
collection area located at the upper portion of the conical
housing.
[0074] In a forty-first aspect of the present disclosure, which may
be combined with the fortieth aspect in combination with any other
aspect listed herein unless specified otherwise, the airtrap has a
toroidal top leading to an inner cone.
[0075] In a forty-second aspect of the present disclosure, any of
the structure and functionality disclosed in connection with FIGS.
1 to 11 may be combined with any of the other structure and
functionality disclosed in connection with FIGS. 1 to 11.
[0076] In light of the present disclosure and the above aspects, it
is therefore an advantage of the present disclosure to provide an
improved air removal device, system and method for renal failure
therapies.
[0077] It is another advantage of the present disclosure to provide
an improved air removal device, system and method for intravenous
drug delivery treatments.
[0078] It is a further advantage of the present disclosure to
provide an air removal device, system and method that is efficient
in trapping air bubbles from blood or medical fluid flow.
[0079] It is still another advantage of the present disclosure to
provide an air removal device, system and method in which trapped
air can be removed from the system, minimizing gas storage space
needed.
[0080] It is still a further advantage of the present disclosure to
provide an air removal device, system and method that minimizes
blood compliment activation and propensity to cause clotting, which
tends to avoid blood recirculation, stagnation and high shear.
[0081] It is yet another advantage of the present disclosure to
provide an air removal device, system and method that may be
primed, rinsed and/or washed for reuse.
[0082] It is yet a further advantage of the present disclosure to
provide an air removal device, system and method that uses
materials of construction that are blood and/or medical fluid
compatible and remain durable when sterilized and/or
disinfected.
[0083] Further still, it is an advantage of the present disclosure
to provide an air removal device, system and method that may reduce
the risk of infusing large air boluses (e.g., >.about.0.5 ml in
volume), bubbles (e.g., .about.1 .mu.L to .about.500 .mu.L in
volume), and microbubbles (e.g., <.about.1 .mu.L in volume).
[0084] The advantages discussed herein may be found in one, or
some, and perhaps not all of the embodiments disclosed herein.
Additional features and advantages are described herein, and will
be apparent from, the following Detailed Description and the
figures.
BRIEF DESCRIPTION OF THE FIGURES
[0085] FIG. 1 is a schematic illustration of one embodiment of a
renal failure therapy employing any of the air removal devices,
systems or methods of the present disclosure.
[0086] FIG. 2 is a perspective view illustrating any of the
airtraps described herein operating with a blood set for use with a
blood treatment machine.
[0087] FIG. 3 is a perspective view of one embodiment of an airtrap
of the present disclosure.
[0088] FIG. 4 is an cross-sectional elevation view of the airtrap
embodiment of FIG. 3.
[0089] FIG. 5 is a solid perspective view of a second embodiment of
an airtrap of the present disclosure.
[0090] FIG. 6 is a see-through perspective view of the second
embodiment of the airtrap of FIG. 5.
[0091] FIG. 7 is a side elevation view of a third embodiment of an
airtrap of the present disclosure.
[0092] FIG. 8 is a top view of the third embodiment of the airtrap
of FIG. 7.
[0093] FIG. 9 is a side elevation view of a modified third
embodiment of the airtrap of the present disclosure.
[0094] FIG. 10 is a perspective view illustrating any of the
airtraps described herein operating with a peritoneal dialysis
fluid set for use with an automated peritoneal dialysis
machine.
[0095] FIG. 11 is an elevation view illustrating any of the
airtraps described herein operating with a drug delivery set for
use with an infusion pump or drug delivery machine.
DETAILED DESCRIPTION
System Hardware
[0096] The examples described herein are applicable to any medical
fluid therapy system that delivers a medical fluid, such as blood,
dialysis fluid, substitution fluid or intravenous drug delivery.
The examples are particularly well suited for kidney failure
therapies, such as all forms of hemodialysis ("HD"), hemofiltration
("HF"), hemodiafiltration ("HDF") and continuous renal replacement
therapies ("CRRT"), referred to herein collectively or generally
individually as renal failure therapy. Moreover, the machines and
any of the airtraps described herein may be used in clinical or
home settings. For example, the machine and any one or more of the
airtraps may be employed in an in-center HD machine, which runs
virtually continuously throughout the day. Alternatively, they may
be used in a home HD machine, which can for example be run at night
while the patient is sleeping. Moreover, each of the renal failure
therapy examples described herein may include a diffusion membrane
or filter, such as a dialyzer, e.g., for HD or HDF, or a
hemofilter, e.g., for HF.
[0097] Referring now to FIG. 1, one embodiment for a renal failure
therapy system 10 employing any of the airtraps and associated
methodology described herein is illustrated using an HD machine.
Generally, system 10 is shown having a very simplified version of
the dialysis fluid or process fluid delivery circuit. The blood
circuit is also simplified but not to the degree that the dialysis
fluid circuit is simplified. It should be appreciated that the
circuits have been simplified to make the description of the
present disclosure easier, and that the systems if implemented
would have additional structure and functionality, such as is found
in the publications incorporated by reference above.
[0098] System 10 of FIG. 1 includes a blood circuit 20. Blood
circuit 20 pulls blood from and returns blood to a patient 12.
Blood is pulled from patient 12 via an arterial line 14, and is
returned to the patient via a venous line 16. Arterial line 14
includes an arterial line connector 14a that connects to an
arterial needle 14b, which is in blood draw flow communication with
patient 12. Venous line 16 includes a venous line connector 16a
that connects to a venous needle 16b, which is in blood return flow
communication with the patient. Arterial and venous lines 14 and 16
also include line clamps 18a and 18v, which can be spring-loaded,
fail-safe mechanical pinch clamps. Line clamps 18a and 18v are
closed automatically in an emergency situation in one
embodiment.
[0099] Arterial and venous lines 14 and 16 also include air or
bubble detectors 22a and 22v, respectively, which can be ultrasonic
air detectors. Air or bubble detectors 20a and 20v look for air in
the arterial and venous lines 14 and 16, respectively. If air is
detected by one of air detectors 22a and 22v, system 10 closes line
clamps 18a and 18v, pauses the blood and dialysis fluid pumps, and
provides instructions to the patient to clear the air so that
treatment can resume.
[0100] A blood pump 30 is located in arterial line 14 in the
illustrated embodiment. In the illustrated embodiment, blood pump
30 includes a first blood pump pod 30a and a second blood pump pod
30b. Blood pump pod 30a operates with an inlet valve 32i and an
outlet valve 32o. Blood pump pod 30b operates with an inlet valve
34i and an outlet valve 34o. In an embodiment, blood pump pods 30a
and 30b are each blood receptacles that include a hard outer shell,
e.g., spherical, with a flexible diaphragm located within the
shell, forming a diaphragm pump. One side of each diaphragm
receives blood, while the other side of each diaphragm is operated
by negative and positive air pressure. Blood pump 30 is
alternatively a peristaltic pump operating with the arterial line
14 tube.
[0101] A heparin vial 24 and heparin pump 26 are located between
blood pump 30 and blood filter 40 (e.g., dialyzer) in the
illustrated embodiment. Heparin pump 26 can be a pneumatic pump or
a syringe pump (e.g., stepper motor driven syringe pump). Supplying
heparin upstream of blood filter 40 helps to prevent clotting of
the blood filter membranes.
[0102] A control unit 50 includes one or more processor and memory.
Control unit 50 receives air detection signals from air detectors
22a and 22v (and other sensors of system 10, such as temperature
sensors, blood leak detectors, conductivity sensors, pressure
sensors, and access disconnection transducers 102, 104), and
controls components such as line clamps 18a and 18v, blood pump 30,
heparin pump 26, and the dialysis fluid pumps.
[0103] Blood exiting blood filter 40 via venous line 16 flows
through an airtrap 110 (referring collectively or generally
individually to any of airtraps 110a to 110c discussed below).
Airtrap 110 removes air from the blood before the dialyzed blood is
returned to patient 12 via venous line 16 as discussed in detail
below.
[0104] With the hemodialysis version of system 10 of FIG. 1,
dialysis fluid or dialysate is pumped along the outside of the
membranes of blood filter 40, while blood is pumped through the
insides of the blood filter membranes. Dialysis fluid or dialysate
is prepared beginning with the purification of water via a water
purification unit 60. One suitable water purification unit is set
forth in U.S. Patent Publication No. 2011/0197971, entitled, "Water
Purification System and Method", filed Apr. 25, 2011, the entire
contents of which are incorporated herein by reference and relied
upon. In one embodiment, water purification unit includes filters
and other structure to purify tap water (e.g., remove pathogens and
ions such as chlorine) so that the water is in one implementation
below 0.03 endotoxin units/ml ("EU/ml") and below 0.1 colony
forming units/ml ("CFU/ml"). Water purification unit 60 can be
provided in a housing separate from the housing of the hemodialysis
machine, which includes blood circuit 20 and a dialysis fluid
circuit 70.
[0105] Dialysis fluid circuit 70 is again highly simplified in FIG.
1 to ease illustration and to better highlight blood circuit 20.
Dialysis fluid circuit 70 in actuality may include all of the
relevant structure and functionality set forth in the publications
incorporated by reference above. Certain features of dialysis fluid
circuit 70 are illustrated in FIG. 1. In the illustrated
embodiment, dialysis fluid circuit 70 includes a to-blood filter
dialysis fluid pump 64. Pump 64 is in one embodiment configured the
same a blood pump 30. Pump 64, like pump 30, includes a pair of
pump pods, which again may be spherically configured. The two pump
pods, like with blood pump 30, are operated alternatingly so that
one pump pod is filling with HD dialysis fluid, while the other
pump pod is expelling HD dialysis fluid.
[0106] Pump 64 is a to-blood filter dialysis fluid pump. There is
another dual pod pump 96, like pump 64, located in drain line 82 to
push used dialysis fluid to drain. There is a third pod pump (not
illustrated) for pumping pump purified water through a bicarbonate
cartridge 72. There is a fourth pod pump (not illustrated) used to
pump acid from acid container 74 into mixing line 62. The third and
fourth pumps, the concentrate pumps, can be single pod pumps
because continuous pumping is not as important in mixing line 62
because there is a buffering dialysis fluid tank (not illustrated)
between mixing line 62 and to-blood filter dialysis fluid pump 64
in one embodiment.
[0107] A fifth pod pump (not illustrated) provided in drain line 82
is used to remove a known amount of ultrafiltration ("UF") when the
HD therapy is provided. System 10 keeps track of the UF pump to
control and know how much ultrafiltrate has been removed from the
patient. System 10 ensures that the necessary amount of
ultrafiltrate is removed from the patient by the end of
treatment.
[0108] Each of the above-described pumps may alternatively be a
peristaltic pump operating with a tube.
[0109] In one embodiment, purified water from water purification
unit 60 is pumped along mixing line 62 though bicarbonate cartridge
72. Acid from container 74 is pumped along mixing line 62 into the
bicarbonated water flowing from bicarbonate cartridge 72 to form an
electrolytically and physiologically compatible dialysis fluid
solution. The pumps and temperature-compensated conductivity
sensors used to properly mix the purified water with the
bicarbonate and acid are not illustrated but are disclosed in
detail in the publications incorporated by reference above.
[0110] FIG. 1 also illustrates that dialysis fluid is pumped along
a fresh dialysis fluid line 76, through a heater 78 and an
ultrafilter 80, before reaching blood filter 40, after which the
used dialysis fluid is pumped to drain via drain line 82. Heater 78
heats the dialysis fluid to body temperature or about 37.degree. C.
Ultrafilter 80 further cleans and purifies the dialysis fluid
before reaching blood filter 40, filtering bugs or contaminants
introduced for example via bicarbonate cartridge 72 or acid
container 74 from the dialysis fluid.
[0111] Dialysis fluid circuit 70 also includes a sample port 84 in
the illustrated embodiment. Dialysis fluid circuit 70 will further
include a blood leak detector (not illustrated but used to detect
if a blood filter 40 fiber is torn) and other components that are
not illustrated, such as balance chambers, plural valves, and a
dialysis fluid holding tank, all illustrated and described in
detail in the publications incorporated by reference above.
[0112] In the illustrated embodiment, hemodialysis system 10 is an
online, pass-through system that pumps dialysis fluid through blood
filter one time and then pumps the used dialysis fluid to drain.
Both blood circuit 20 and dialysis fluid circuit 70 may be hot
water disinfected after each treatment, such that blood circuit 20
and dialysis fluid circuit 70 may be reused. In one implementation,
blood circuit 20 including blood filter 40 is hot water disinfected
and reused daily for about one month, while dialysis fluid circuit
70 is hot water disinfected and reused for about six months.
[0113] In alternative embodiments, or for CRRT for example,
multiple bags of sterilized dialysis fluid or infusate are ganged
together and used one after another. In such a case, the emptied
supply bags can serve as drain or spent fluid bags.
[0114] The machine 90 of system 10 includes an enclosure as
indicated by the dotted line of FIG. 1. The enclosure of machine 90
varies depending upon the type of treatment, whether the treatment
is in-center or a home treatment, and whether the dialysis
fluid/infusate supply is a batch-type (e.g., bagged) or on-line.
Although not illustrated in FIG. 1, the front of the enclosure of
machine 90 may have structures configured to releaseably clamp any
of the airtraps 110 discussed herein in place and in their
appointed configurations. For example, the conical airtrap 110a
that narrows as it extends from bottom to top can be slid
horizontally into a triangular bracket that extends from the front
of the enclosure of machine 90, which holds conical airtrap 110a
releaseably upright in its proper operating position. On the other
hand, the conical airtrap 110b that narrows as it extends from top
to bottom can be slid downwardly into fork-like structures that
extend from the front of the enclosure of machine 90, which holds
conical airtrap 110b releaseably upright in its proper operating
position. Seahorse airtrap 110c can be held releaseably in place
via plural spring clips that extend from the front of the enclosure
of machine 90.
[0115] FIG. 2 illustrates that machine 90 of system 10 of FIG. 1
may operate with a blood set 100. Blood set 100 includes arterial
line 14, venous line 16, heparin vial 24 and heparin pump 26/blood
pump 30 and blood filter 40 (e.g., dialyzer). Any of the airtraps
110 discussed herein may be located in venous line 16 to remove air
from the blood before being returned to patient 12. Alternatively
or additionally, any of the airtraps 110 discussed herein may be
located in arterial line 14, e.g., between blood pump 30 and blood
filter 40 (e.g., dialyzer), so as to receive blood under positive
pressure. Further alternatively or additionally, any of the
airtraps 110 discussed herein may be located in dialysate circuit,
in mixing line 62 and/or fresh dialysis fluid line 76 to improve
mixing accuracy and/or to remove air from fresh dialysis fluid line
before reaching filter or dialyzer 40.
Airtraps
[0116] Referring now to FIGS. 3 and 4, one embodiment of an airtrap
of the present disclosure is illustrated by airtrap 110a. Airtrap
110a includes a conical housing 112 that can be made of any
medically acceptable material safe for contact with medical,
biological or physiological fluid, such as blood, dialysis fluid,
replacement or substitution fluid, or intravenous drug. Such
materials include medically safe plastics or metals, such as
silicone, polyvinylidene fluoride or polyvinylidene difluoride
("PVDF"), polysulfone, Kynar, silicone-based or silicone-coated
materials, medical grade stainless steel, titanium and combinations
thereof.
[0117] Conical housing 112 includes a top 114, bottom 116, outer
conical wall 118, inner conical wall 120, inlet 122 and outlet 124.
Inlet 122 and outlet 124 may have any suitable connections for
connection to a medic fluid tube or pipe, such as compression
connections, hose barb connections, threaded connections, luer lock
connections and the like. Inlet 122 and outlet 124 are at least
substantially horizontal when airtrap 110a is mounted in its
operating position. Inlet 122 feeds into an upper portion, near the
top 114 of conical housing 112. Outlet 124 extends from a lower
portion, near the bottom 116 of conical housing 112. As
illustrated, outer conical wall 118 increases in diameter as it
extends from top 114 to bottom 116, therefore, outlet 124 resides
further radially outwardly from a central axis of housing 112 than
does inlet 122.
[0118] Inner conical wall 120 extends up from the bottom 116 of
conical housing inside of outer conical wall 118. Inner conical
wall 120 may strike a lesser angle (.alpha.) relative to horizontal
(e.g., 15 to 35 degrees) than does an angle (.beta.) of outer
conical wall 118 (e.g., 40 to 70 degrees). The gap between inner
conical wall 120 and outer conical wall 118 forms the fluid/gas
separation chamber for airtrap 110a. This chamber may have a volume
from about ten cm.sup.3 to about twenty cm.sup.3.
[0119] Inner conical wall 120 and outer conical wall 118 along with
the orientation and placement of inlet 122 and 124 cause any of the
fluids described herein to spin from the top portion of housing 112
to the bottom portion of housing 112 in an increasing arc (as
indicated by dash-dot arrows). The spinning centripetally causes
heavier fluid to migrate towards outer conical wall 118 and lighter
gas or air to separate and migrate towards inner conical wall 120.
Air or gas moves buoyantly centrally up along inner conical wall
120 to the central top 114 of housing 112 in gas collection area
150.
[0120] Central top 114 of housing 112 of airtrap 110a may have any
one of multiple configurations. In one embodiment, top 114 is a
solid structure, wherein released air or gas remains trapped at the
central top 114 of housing 112 over one or more treatment, or one
or more cycles of a single treatment, after which airtrap 110a is
discarded. In a manual air removal embodiment, central top 114 of
housing 112 includes a septum (not illustrated) that may be
sealingly pierced by a sterile needle to remove air during or after
a treatment. Here, airtrap 110a, may be reused over multiple
treatments. In an automatic air removal embodiment, central top 114
of housing 112 is placed in valved connection with an air line and
air pump (not illustrated), which under control of control unit 50
automatically pulls air from housing 112 at desired intervals. Here
again, airtrap 110a, may be reused over multiple treatments.
[0121] In the illustrated embodiment, central top 114 of housing
112 of airtrap 110a includes a passive air removal structure, which
includes a one-way or check gas release valve assembly 130. One-way
or check gas release valve assembly 130 includes a valve housing
132 holding a flexible valve 134. Flexible valve 134 may be
silicone or any of the flexible materials discussed herein.
Flexible valve 134 may include a stem 136 that is crimped to valve
housing 132 and a valve seat 138 formed with or attached to valve
stem 136. Stem 136 is held under tension against valve housing 132,
so as to pull valve seat 138 sealingly against valve housing 132,
closing valve assembly 130 and trapping gas or air within airtrap
housing 112. Gas or air under pressure within airtrap housing 112
pushes against valve seat 138, tending to open the valve seat. When
the gas or air pressure builds to a predefined level, e.g., 100 to
300 mmHg, valve seat 138 becomes unseated from valve housing 132,
allowing gas or air to burp out of airtrap 110a, relieving gas or
air pressure. Once pressure is relieved, stem 136 pulls seat 138
self-sealingly back against valve housing 132. This burping or
purging cycle may be repeated one or more time during a single or
multiple treatments.
[0122] In the illustrated embodiment, as part of or in addition to
valve assembly 130, a hydrophobic filter 140 (air passing but
liquid retaining), e.g., in the form of a circular wafer, may be
placed beneath valve stem 136 and valve seat 138 to prevent liquid
or fluid within housing 112 from escaping airtrap 110a when valve
assembly 130 is burped as described previously. Hydrophobic filter
140 in an embodiment is made of polyvinylidene fluoride or
polyvinylidene difluoride ("PVDF"). Hydrophobic filter 140 may be
held in place against airtrap housing 112 or valve housing 132 via
a polysulfone or other material fixing ring 142, which may be
welded to, formed with, adhered or attached to airtrap housing 112
or valve housing 132.
[0123] FIG. 4 also illustrates that airtrap 110a may be held
removeably in place via a bracket 144 that extends from the chassis
of machine 90. Bracket 144 may be formed integrally with the front
panel of machine 90 (e.g., part of a molded plastic front panel) or
be attached to the front panel. In the illustrated embodiment,
bracket 144 is triangular shaped, including a horizontal bottom
wall 146 and angled arms 148a and 148b extending up from bottom
wall 146 at an angle coinciding with the angle of outer conical
wall 118 (e.g., 40 to 70 degrees). Angled arms 148a and 148b do not
extend fully to form a complete triangle and instead stop to allow
for the at least substantially flat top 114 of airtrap 110a.
Bracket 144 extends a distance from the front panel of machine 90
sufficient to hold airtrap 110a firmly in place, however, the
bracket stops short of inlet 122 and outlet 124, so as to allow
tubes (not illustrated) to run freely to and from the inlet and
outlet, respectively. Bracket 144 as illustrated holds airtrap 110a
in its proper position for operation. Bracket 144 also allows for
the ready insertion and removal of airtrap 110a.
[0124] The housings of both airtraps 110a and 110b may also include
smooth fluid contacting surfaces to reduce or prevent eddy
currents.
[0125] Referring now to FIGS. 5 and 6, another embodiment of an
airtrap of the present disclosure is illustrated by airtrap 110b.
Airtrap 110b again includes a conical housing 152 that may be made
of any medically acceptable material safe for contact with medical,
biological or physiological fluid, such as blood, dialysis fluid,
replacement or substitution fluid, or intravenous drug. Such
materials include medically safe plastics or metals, such as
silicone, polyvinylidene fluoride or polyvinylidene difluoride
("PVDF"), polysulfone, Kynar, silicone-based or silicone-coated
materials, medical grade stainless steel, titanium and combinations
thereof.
[0126] Conical housing 152 in the illustrated embodiment includes a
toroidal top 154, bottom 156, outer conical wall 158, inner conical
wall or cone 160, inlet 162 and outlet 164. Inlet 162 and outlet
164 may have any suitable connections for connection to a medic
fluid tube or pipe, such as compression connections, hose barb
connections, threaded connections, luer lock connections and the
like. Inlet 162 is at least substantially horizontal when airtrap
110b is mounted in its operating position. Inlet 162 feeds into an
upper portion, near the top 154 of conical housing 152. Outlet 164
in the illustrated embodiment extends vertically downwardly from a
lower portion, at or near the bottom 156 of conical housing 152. As
illustrated, outer conical wall 158 in this embodiment decreases in
diameter as it extends from top 154 to bottom 156, therefore, inlet
162 resides further radially outwardly from a central axis of
housing 112 than does outlet 164, which as illustrated can reside
along the central axis.
[0127] Inner conical wall or cone 160 extends down from the top 154
of conical housing 152 inside of outer conical wall 158. Inner
conical wall 160 may strike a greater angle (a) relative to
horizontal (e.g., 60 to 88 degrees) than does an angle ((3) of
outer conical wall 158 (e.g., 40 to 70 degrees). The gap between
inner conical wall or cone 160 and outer conical wall 158 forms the
fluid/gas separation chamber for airtrap 110b. This chamber may
have a volume from about eight cm.sup.3 to about eighteen
cm.sup.3.
[0128] Inner conical wall or cone 160 and outer conical wall 158
along with the orientation and placement of inlet 162 and outlet
164 cause any of the fluids described herein to spin from the top
portion of housing 152 to the bottom portion of housing 152 in a
decreasing arc (as indicated by dash-dot arrows). The fluid
spinning centripetally causes heavier fluid to migrate towards
outer conical wall 158 and lighter gas or air to separate and
migrate towards inner conical wall or cone 160. Air or gas moves
buoyantly centrally up along inner conical wall or cone 160 to the
peripheral top 154 of housing 152.
[0129] The periphery of toroidal composite top 154 of housing 152
of airtrap 110b may have any of the air trapping, manual air
removal, active air removal or passive air removal configurations
described above for airtrap 110a.
[0130] FIG. 6 also illustrates that airtrap 110b may be held
removeably in place via a pair of fork-like structures 166 and 168
that extend from the chassis of machine 90. Fork-like structures
166 and 168 may be formed integrally with the front panel of
machine 90 (e.g., part of a molded plastic front panel) or be
attached to the front panel. In the illustrated embodiment,
fork-like structure 166 is wider in diameter and sized to
releaseably capture an upper portion of housing 152 of airtrap
110b, while fork-like structure 168 is narrower in diameter and
sized to releaseably capture, e.g., snap-fit to, a lower portion of
housing 152. Lower fork-like structure 168 may for example snap-fit
to a fixed diameter tube of outlet 164. Fork-like structures 166
and 168 extend a distance from the front panel of machine 90
sufficient to hold airtrap 110b firmly in place, without tilting,
and to allow tubes (not illustrated) to run freely to and from the
inlet 162 and outlet 164, respectively. Fork-like structures 166
and 168 as illustrated hold airtrap 110b in its proper position for
operation. Fork-like structures 166 and 168 also allow for the
ready insertion and removal of airtrap 110b.
[0131] Referring now to FIGS. 7 to 9, a further embodiment of an
airtrap of the present disclosure is illustrated by airtrap 110c.
Airtrap 110c includes a seahorse-shaped housing 172, which may be
made of any medically acceptable material safe for contact with
medical, biological or physiological fluid, such as blood, dialysis
fluid, replacement or substitution fluid, or intravenous drug. Such
materials again include medically safe plastics or metals, such as
silicone, polyvinylidene fluoride or polyvinylidene difluoride
("PVDF"), polysulfone, Kynar, silicone-based or silicone-coated
materials, medical grade stainless steel, titanium and combinations
thereof.
[0132] Seahorse-shaped housing 172 includes a head section 174 and
a tail section 176 extending from head section 174. Tail section
176 may be curved, straight, have jogs and/or undulations 177 as
desired. Head section 174 forms an inlet 178, while the distal end
of tail section 176 forms and outlet 180. Inlet 178 and outlet 180
may have any suitable connections for connection to a medic fluid
tube or pipe, such as compression connections, hose barb
connections, threaded connections, luer lock connections and the
like. Inlet 178 is at least substantially horizontal when airtrap
110b is mounted in its operating position. Inlet 178 feeds into
head section 174, near the top of seahorse-shaped housing 172.
Outlet 180 in the illustrated embodiment also extends at least
substantially horizontally at the bottom of tail section 176.
[0133] Head section 174 in an embodiment (i) if rounded includes a
largest diameter extending perpendicular to a plane bisecting
airtrap 110b or (ii) if non-rounded (e.g., rectangular or square
shape) includes a largest width and height extending perpendicular
to the plane bisecting the airtrap. Tubular tail section 176 is
structured in an embodiment such that when airtrap 110c is mounted
for operation, tail section 176 extends downwardly from head
section 174, and wherein tubular tail section 176 (a) if circular
in cross-section is smaller in diameter or (b) if non-circular in
cross-section is smaller in its largest cross-sectional distance
than (i) the largest diameter of the head section or (ii) the
largest width and height of the head section.
[0134] The head section 174 may form an enlarged hump before
gradually narrowing as directed through tail section 176 downward
to outlet 180. Head section 174, tail section 176, inlet 178 and
outlet 180 may be constructed, positioned and arranged so that
medical or physiological fluid flow initially expands and slows,
separating and storing air in head section 174, while thereafter
gradually accelerating from inlet 178 to outlet 180.
[0135] Airtrap 110c relies mainly on buoyancy forces to all air or
gas to separate from whatever fluid is flowing through the airtrap.
Tail section 176 provides a relatively long and at least somewhat
vertical length, providing time and opportunity for air or gas to
bubble up to head section 174. FIG. 9 illustrates that head section
174 may be larger to hold more air or gas. The internal volume of
seahorse-shaped housing 172 may be about seven cm.sup.3 to about
seventeen cm.sup.3. Tail section 176 may be curved, have jogs
and/or undulations 177 to change the direction of fluid flowing
through airtrap 110b and to help separate the bubbles from the
liquid.
[0136] The top of head section 174 of housing 172 of airtrap 110b
may have any of the air trapping, manual air removal, active air
removal or passive air removal configurations described above for
airtrap 110a.
[0137] FIGS. 7 and 8 also illustrate that airtrap 110c may be held
removeably in place via a pair of spring clips 186 and 188 that
extend from the chassis of machine 90. Spring clips 186 and 188 may
be formed integrally with the front panel of machine 90 (e.g., part
of a molded plastic front panel) or be attached to the front panel.
In the illustrated embodiment, spring clip 186 is wider and sized
to releaseably capture an upper portion of tail section 176 of
housing 172 of airtrap 110c, while spring clip 188 is narrower and
sized to releaseably capture a lower portion of the tail section.
Spring clips 186 and 188 extend a distance from the front panel of
machine 90 sufficient to hold airtrap 110b firmly in place, without
tilting, and to allow tubes (not illustrated) to run freely to and
from the inlet 178 and outlet 180, respectively. Spring clips 186
and 188 as illustrated hold airtrap 110c in its proper position for
operation. Spring clips 186 and 188 also allow for the ready
insertion and removal of airtrap 110c.
[0138] With any of airtraps 110a to 110c, it is contemplated that
that the inside surface of the wall forming the fluid chamber and
the outside surface of the wall forming the fluid chamber have the
same shape or roughly the same shape, e.g., with a constant wall
thickness. This is illustrated in FIG. 4 for example where outer
wall 118 of airtrap 110a, for example, has a constant thickness and
the outside of housing 112 has a conical shape just as does the
inside of conical housing 112. It should be appreciated however
that "conical housing" additionally means just the inside surface
of the chamber defining wall, where the outside surface could be
any desired shape, e.g., cylindrical, rectangular, etc. In this
latter embodiment, the spiraling flowpath is still obtained. The
same is true for conical housing 152 of airtrap 110b. Additionally,
any conical housing of the present disclosure may be partially
conical, and not totally conical, e.g., having a flattened top or
bottom.
[0139] The head section 174 and tubular tail section 176 of
seahorse-shaped housing 172 can likewise look like a seahorse from
the outside or only have the seahorse shape on the inside
fluid-contacting surface. If the seahorse shape is provided only on
the inside, fluid-contacting surface, the outer surface of housing
172 may instead be cylindrical or rectangular, for example. The
flowpath of fluid through head section 174 and tubular tail section
176 is the same regardless.
[0140] The following chart sets forth certain example performance
and physical characteristics comparing and contrasting the
different airtraps 110a to 110c. Regarding the ability to remove
air, airtraps 110a and 110c both performed very well, while airtrap
110c removed somewhat less air, but still performed well.
[0141] Regarding the amount of air that each airtrap can hold,
airtraps 110a to 110c again perform better than airtrap 110b in the
example illustrated below. Air trapping saturation volume is the
volume of air that each airtrap 110a to 110c can store in its upper
chamber (without air removal) before the air starts to become
reinfused into the blood or other physiological fluid. Thus, if an
entire treatment is only expected to produce 7.0 ml of air, then
airtraps 110a and 110c may be used without any of the air removal
techniques discussed herein. Airtrap 110b would however need some
type of manual, passive or active air removal during treatment. If
the entire treatment is expected instead to produce 15.0 ml of air,
then each airtrap 110a to 110c would require some type of manual,
passive or active air removal during treatment.
[0142] A smaller amount of blood volume is better generally because
there is less blood to rinse back to the patient after treatment
and if for some reason blood cannot be rinsed back to the patient,
perhaps after a more severe alarm event, there is less blood
trapped in the blood set. For other physiological fluids, e.g.,
dialysis fluid, water, saline, or liquid drug, airtrap volume is
not as important. Regarding fluid volume in the examples below,
airtrap 110b has the lowest volume, while airtrap 110a has around
twice the volume as airtrap 110b.
[0143] Other factors besides those shown in the below chart include
manufacturability and the ability to house or have air removal
structure. Regarding these features, airtrap 110a is likely the
most desirable. Airtrap 110a has a relatively simple shape compared
with airtraps 110b and 110c, likely making airtrap 110a easier to
mold and manufacture. Regarding air removal, passive air removal is
likely the most desirable. Manual air removal as its same implies
needs manual attention. Active air removal requires more equipment,
such as an air pump and valve, e.g., solenoid or pneumatically
operated valve. Passive air removal operates automatically like
active air removal but needs no automatic actuation. The example
structures discussed above for providing passive air removal are
likely easiest to implement onto airtrap 110a. Airtrap 110a may
employ flat top 114, which provides a convenient location for valve
assembly 130 and hydrophobic filter 140.
TABLE-US-00001 Trap 110a Trap 110b Trap 110c (FIGS. 3, 4) (FIGS. 5,
6) (FIGS. 7, 8, 9) Air Trapped (%) 97 86 100 Air Trapping
Saturation 9.0 5.8 11.9 Volume (ml) Blood (Liquid) 32.9 15.3 20.2
Volume (ml)
Performance/Physical Characteristics Chart
Additional Alternative Embodiments
[0144] As discussed above, any of airtraps 110a to 110c may be used
in a blood treatment system 10, e.g., as part of a blood set 100
and/or within dialysis fluid circuit 70. In an alternative
embodiment illustrated in connection with FIG. 10, any of airtraps
110a to 110c may be operated instead with an automated peritoneal
dialysis ("APD") machine 190. APD machine 190 is sometimes called a
cycler because it typically performs multiple drain, fill and dwell
cycles. During drain cycles, APD machine 190 places a patient line
192 under negative pressure to pull used dialysate from a patient's
peritoneal cavity. The patient line 192 is in fluid communication
with a disposable cassette 194, which operates with APD machine 190
to pump peritoneal dialysis fluid to and from patient 12.
[0145] Patient line 192, disposable cassette 194 may form an
overall disposable set along with a drain bag 196, one or more
supply bags 198 and associated tubing. During fill cycles, APD
machine 190 operating disposable cassette 194 places patient line
192 under positive pressure to push new dialysate from the machine
to the patient's peritoneal cavity. During the dwell cycles,
peritoneal dialysis fluid is left to dwell within the patient's
peritoneal cavity.
[0146] Any of airtraps 110a to 110c may be placed in patient line
192, for example, at or near APD machine 190, so that airtraps 110a
to 110c may be mounted in their proper operating positions and
orientations on the chassis of APD machine 190. Airtraps 110a to
110c may each be mounted to the chassis of machine 190 via any of
the structures and methodology discussed above for blood treatment
machine 90. The cassette and patient line 192 for APD machine 190
is typically single use, so airtraps 110a to 110c for this
application may simply trap and hold air over the course of
treatment. It is contemplated however that airtraps 110a to 110c
for APD machine 190 may alternatively employ manual air removal
(e.g., via a septum) or passive air removal (e.g., via a filter and
check valve).
[0147] When APD machine 190 is pulling used dialysis fluid from
patient 12 via patient line 192, the fluid within the patient line
is under negative pressure. In this instance, air may not be
removed as easily within airtraps 110a to 110c. Importantly,
however, when APD machine 190 is pushing fresh dialysis fluid to
patient 12 via patient line 192, the fluid within the patient line
is under positive pressure. In this more critical instance (because
fluid is being delivered to patient 12), air is removed readily
within airtraps 110a to 110c.
[0148] While FIG. 10 illustrates airtraps 110a to 110c operating
with an APD machine 190, it should be appreciated however that
airtraps 110a to 110 could alternatively be used with a continuous
ambulatory peritoneal dialysis set ("CAPD", not illustrated), which
is manual peritoneal dialysis. Here, the patient is instructed to
temporarily mount or attach airtraps 110a to 110c to a structure,
such as a tabletop, so as to be maintained in a proper operating
orientation during treatment. Airtraps 110a to 110c may be provided
with structures, e.g., spring-loaded clamps for doing so.
[0149] In a further alternative embodiment illustrated in
connection with FIG. 11, any of airtraps 110a to 110c may be
operated instead with an infusion pump 290 for administering one or
more drugs to a patient via a drug delivery line 292. Infusion pump
290 may for example be a large volume infusion pump ("LVP"), which
typically employs a rotary or peristaltic pump actuator or a
shuttle pump actuator 294. Infusion pump 290 may alternatively be a
syringe pump, which employs a syringe pump actuator 294. Drug
delivery line 292 in the illustrated embodiment forms a drug
delivery set 300 along with a source 296 of intravenous drug (which
may be a bagged source, syringe source or other suitable
source).
[0150] Any of airtraps 110a to 110c may be placed in patient line
drug delivery line 292 downstream of pump actuator 294, for
example, at or near infusion pump 290, so that airtraps 110a to
110c may be mounted in their proper operating positions and
orientations on the chassis of infusion pump 290. Airtraps 110a to
110c may each be mounted to the chassis of infusion pump 290 via
any of the structures and methodology discussed above for blood
treatment machine 90. The pumping set including drug delivery line
292 for infusion pump 290 is typically single use, so airtraps 110a
to 110c for this application may simply trap and hold air over the
course of treatment. It is contemplated however that airtraps 110a
to 110c for infusion pump 290 may alternatively employ manual air
removal (e.g., via a septum) or passive air removal (e.g., via a
filter and check valve).
[0151] Drug delivery line 292 downstream of pump actuator 294 is
typically only under positive pressure to push one or more drug to
patient 12. Here, air is removed readily from the one or more drug
within airtraps 110a to 110c.
[0152] It should be understood that various changes and
modifications to the presently preferred embodiments described
herein will be apparent to those skilled in the art. Such changes
and modifications can be made without departing from the spirit and
scope of the present subject matter and without diminishing its
intended advantages. It is therefore intended that such changes and
modifications be covered by the appended claims.
* * * * *